1. Field of the Invention
This invention relates generally to the rectification of an extended off-hook condition of an unused telephone line by customer premises equipment. More particularly, it relates to the presentation of an improved off-hook notification to a user of a telephone line including a telephone receiver left in an extended off-hook condition.
2. Background of Related Art
At various times, a telephone line may be inadvertently placed in an off-hook condition for an extended period of time even when the telephone line is not in an established telephone call. For instance, the receiver may not be properly returned to the cradle of the telephone system after a telephone call, or a handset may be accidentally dislodged from the cradle of its telephone system or base unit, etc. When in an off-hook condition, the telephone line is typically incapacitated because, e.g., it is not able to audibly ring the telephone when a new incoming call is received. Thus, it is desirable to have the user of the telephone correct the problem, e.g., physically hang up the handset to avoid lost incoming calls.
When an extended off-hook condition occurs, the telephone company central office conventionally sends a high energy extended off-hook (EOH) notification signal to the telephone line. Presumably, the off-hook handset or speaker will output the received high energy EOH signal as a loud audible tone. If the user of the telephone line is within an audible distance of the off-hook receiver, they will presumably hear the receiver off-hook notification signal, recognize the problem, and subsequently return the off-hook receiver into its proper place to return the telephone line to an on-hook condition. If the user of the telephone line is not within an audible distance of the off-hook receiver, the telephone line will remain in an off-hook condition until noticed at a later time by the user. Typically, the audible EOH tone is terminated after a predetermined amount of time, and the telephone line may be temporarily disconnected at the central office until the off-hook condition is corrected.
FIG. 6 illustrates a conventional telephone system capable of receiving an extended off-hook (EOH) notification signal from the telephone company central office.
In particular, in FIG. 6, a telephone system 11 is connected to a telephone company central office 13 via a telephone line 15. The telephone company central office 13 is typically considered to be a part of the public switched telephone network 17.
The telephone system 11 includes a telephone base unit 19 having a cradle 21 for receiving a handset 23. When the handset 23 is properly placed in the cradle 21, a switch in the telephone notifies a telephone line interface in the telephone system 11 to place the telephone line in an on-hook condition. In an on-hook condition the telephone system 11 is capable of receiving an incoming telephone call (and of placing an outgoing telephone call) over the telephone line 15.
If the handset 23 is inadvertently displaced or otherwise removed from the cradle 21 of the telephone base unit 19 of the telephone system 11 for an extended period of time when the telephone system 11 is not in use, the telephone company central office 13 will detect such an off-hook condition and recognize that the telephone system 11 is not in an established telephone call. Thus, in an attempt to notify the user to rectify the situation, the central office 13 will output an extended off-hook (EOH) notification signal to the telephone line 15 for audible and/or visual display at the off-hook telephone system 11. The receiver off-hook notification signal can be audibly heard (and/or visually observed using an appropriate display) to a user within an audible and/or visual distance of the handset 23.
Unfortunately, many times a user is no longer within an audible distance of the handset 23 when the extended off-hook (EOH) notification signal is finally presented by the telephone company central office 13 over the telephone line 15. For instance, the user may have been on their way out of the house to drive to the office as soon as they completed the last telephone call using the offending telephone system 11, and may no longer be in the house when the extended off-hook (EOH) notification signal is finally transmitted by the central office 13 to the user""s off-hook telephone system 11, or may return after the unsuccessful extended off-hook (EOH) signal is no longer being transmitted by the central office 13. As another example, a user may inadvertently or unknowingly activate a xe2x80x9ctalkxe2x80x9d or xe2x80x9cphonexe2x80x9d button on the handset of a remote cordless telephone, unintentionally causing the telephone line to go off-hook.
Thus, since the user may not be within an audible and/or visual distance of the off-hook handset 23 when the extended off-hook (EOH) signal is received, they will likely not realize that the handset 23 is in an off-hook condition. As a result, the user will then not be able to receive incoming telephone calls over the telephone line 15 or to record incoming voice messages on an appropriate voice messaging system. Many hours of telephone calls may be lost due to the inadvertent off-hook condition of the telephone system 11. Another disadvantage is that the status of the called telephone line is unknown to the caller when receiving a busy signal.
Accordingly, there exists a need for an apparatus and method having an improved alerting mechanism and method which has an increased probability of success, i.e., having the user return the off-hook receiver 13 to the on-hook state.
In accordance with the principles of the present invention, in an on-hook telephone device, a capability to inform a user of an extended off-hook condition in a parallel telephone set comprises a parallel set detector to detect an off-hook condition of a parallel telephone set. An extended off-hook signal detector detects a presence of an extended off-hook signal from a central office while the telephone device is in an on-hook condition.
An on-hook notifying telephone of an extended off-hook condition in accordance with another aspect of the present invention comprises a telephone device, a parallel set detector in the telephone device, and an extended off-hook signal detector in the telephone device capable of detecting a presence of an extended off-hook signal on a telephone line to the telephone device while the telephone device is in an on-hook condition.
A method of indicating an extended off-hook condition of a parallel telephone set in accordance with another aspect of the present invention comprises detecting use of a parallel first telephone set on a second telephone set. While the use is detected of the parallel first telephone set, a presence of an extended off-hook signal from a central office is detected from the second telephone set. An alarm signal is output at the second telephone set relating to an extended off-hook condition of the parallel first telephone set.